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Commit 5f995323 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
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sysfs: consolidate sysfs spinlocks 



Replace sysfs_lock and kobj_sysfs_assoc_lock with sysfs_assoc_lock.
sysfs_lock was originally to be used to protect sysfs_dirent tree but
mutex seems better choice, so there is no reason to keep sysfs_lock
separate.  Merge the two spinlocks into one.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 608e266a

fs/sysfs/dir.c

+9 −10
Original line number Diff line number Diff line
@@ -15,8 +15,7 @@ 
#include "sysfs.h"



DECLARE_RWSEM(sysfs_rename_sem);

spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;

spinlock_t kobj_sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;

spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;



static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;

static DEFINE_IDA(sysfs_ino_ida);
@@ -236,10 +235,10 @@ static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) 
	struct sysfs_dirent * sd = dentry->d_fsdata;



	if (sd) {

		/* sd->s_dentry is protected with sysfs_lock.  This

		 * allows sysfs_drop_dentry() to dereference it.

		/* sd->s_dentry is protected with sysfs_assoc_lock.

		 * This allows sysfs_drop_dentry() to dereference it.

		 */

		spin_lock(&sysfs_lock);

		spin_lock(&sysfs_assoc_lock);



		/* The dentry might have been deleted or another

		 * lookup could have happened updating sd->s_dentry to
@@ -248,7 +247,7 @@ static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) 
		 */

		if (sd->s_dentry == dentry)

			sd->s_dentry = NULL;

		spin_unlock(&sysfs_lock);

		spin_unlock(&sysfs_assoc_lock);

		sysfs_put(sd);

	}

	iput(inode);
@@ -298,9 +297,9 @@ static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) 
	dentry->d_fsdata = sysfs_get(sd);



	/* protect sd->s_dentry against sysfs_d_iput */

	spin_lock(&sysfs_lock);

	spin_lock(&sysfs_assoc_lock);

	sd->s_dentry = dentry;

	spin_unlock(&sysfs_lock);

	spin_unlock(&sysfs_assoc_lock);



	d_rehash(dentry);

}
@@ -603,9 +602,9 @@ void sysfs_remove_dir(struct kobject * kobj) 
{

	struct sysfs_dirent *sd = kobj->sd;



	spin_lock(&kobj_sysfs_assoc_lock);

	spin_lock(&sysfs_assoc_lock);

	kobj->sd = NULL;

	spin_unlock(&kobj_sysfs_assoc_lock);

	spin_unlock(&sysfs_assoc_lock);



	__sysfs_remove_dir(sd);

}

fs/sysfs/inode.c

+8 −8
Original line number Diff line number Diff line
@@ -211,11 +211,11 @@ void sysfs_instantiate(struct dentry *dentry, struct inode *inode) 
 *	parent on entry to this function such that it can't be looked

 *	up anymore.

 *

 *	@sd->s_dentry which is protected with sysfs_lock points to the

 *	currently associated dentry but we're not holding a reference

 *	to it and racing with dput().  Grab dcache_lock and verify

 *	dentry before dropping it.  If @sd->s_dentry is NULL or dput()

 *	beats us, no need to bother.

 *	@sd->s_dentry which is protected with sysfs_assoc_lock points

 *	to the currently associated dentry but we're not holding a

 *	reference to it and racing with dput().  Grab dcache_lock and

 *	verify dentry before dropping it.  If @sd->s_dentry is NULL or

 *	dput() beats us, no need to bother.

 */

void sysfs_drop_dentry(struct sysfs_dirent *sd)

{
@@ -224,9 +224,9 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd) 
	struct inode *inode;



	/* We're not holding a reference to ->s_dentry dentry but the

	 * field will stay valid as long as sysfs_lock is held.

	 * field will stay valid as long as sysfs_assoc_lock is held.

	 */

	spin_lock(&sysfs_lock);

	spin_lock(&sysfs_assoc_lock);

	spin_lock(&dcache_lock);



	/* drop dentry if it's there and dput() didn't kill it yet */
@@ -238,7 +238,7 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd) 
	}



	spin_unlock(&dcache_lock);

	spin_unlock(&sysfs_lock);

	spin_unlock(&sysfs_assoc_lock);



	dput(dentry);

	/* XXX: unpin if directory, this will go away soon */

fs/sysfs/symlink.c

+3 −3
Original line number Diff line number Diff line
@@ -82,12 +82,12 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char 
		return -EFAULT;



	/* target->sd can go away beneath us but is protected with

	 * kobj_sysfs_assoc_lock.  Fetch target_sd from it.

	 * sysfs_assoc_lock.  Fetch target_sd from it.

	 */

	spin_lock(&kobj_sysfs_assoc_lock);

	spin_lock(&sysfs_assoc_lock);

	if (target->sd)

		target_sd = sysfs_get(target->sd);

	spin_unlock(&kobj_sysfs_assoc_lock);

	spin_unlock(&sysfs_assoc_lock);



	if (!target_sd)

		return -ENOENT;

fs/sysfs/sysfs.h

+1 −2
Original line number Diff line number Diff line
@@ -81,8 +81,7 @@ extern void sysfs_remove_subdir(struct sysfs_dirent *sd); 
extern void sysfs_drop_dentry(struct sysfs_dirent *sd);

extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);



extern spinlock_t sysfs_lock;

extern spinlock_t kobj_sysfs_assoc_lock;

extern spinlock_t sysfs_assoc_lock;

extern struct rw_semaphore sysfs_rename_sem;

extern struct super_block * sysfs_sb;

extern const struct file_operations sysfs_dir_operations;